1. Field of the Invention
The present invention relates to a projection display device for modulating light from a light source by an imager, and enlarging and projecting the modulated light onto a projection plane.
2. Disclosure of Related Art
Conventionally, a projection display device (hereinafter, called as a “projector”) such as a liquid crystal projector is configured such that light (hereinafter, called as “image light”) modulated by an imager such as a liquid crystal panel is projected onto a projection plane by a projection lens. In such a projector, heat is generated in e.g. a light source, an imager, and a power source unit. In view of this, it is required to cool these heat generating members.
In such a projector, there may be used an arrangement that air drawn from the outside of the projector is supplied to the heat generating members, and air that has been warmed by heat exchange with the heat generating members is discharged to the outside of the projector to thereby cool the heat generating members. In this case, for instance, an exhaust fan is disposed in a main body cabinet, and air sucked by the exhaust fan is discharged to the outside of the projector through an air outlet formed in the main body cabinet.
The air outlet of the main body cabinet may be formed in various surfaces (upper and lower surfaces, left and right surfaces, and front and rear surfaces) of the main body cabinet in positional relation to components such as a light source and an imager.
In recent years, a so-called short focus projector operable to project an image onto a projection plane (such as a screen) with a shorter distance has been commercialized. In such a projector, the divergence angle of image light is relatively large. Further, air discharged through the air outlet spreads to some extent as it propagates. As a result, the discharged air may overlap with image light, depending on the position of the air outlet. Since the discharged air has a relatively high temperature, if such a high-temperature air overlaps with image light, an image projected onto the projection plane may become obscure.